South Korea reported 125 additional cases of COVID-19 on Thursday, staying above 100 after it returned to triple digits on Wednesday for the first time in three days.
The national caseload is now more than 27-thousand.
Of the new cases, 108 were locally transmitted and 17 imported.
Most of them are from the greater capital area, with 46 in Seoul and 23 from the surrounding Gyeonggi-do Province.
Health authorities are on guard as cluster infections continue to pop up amid the colder weather and the crowds of people out celebrating Halloween last weekend.
At a call center in Cheonan City, Chungcheonnam-do Province, at least 20 employees have tested positive.
According to local officials, a 40-year-old woman tested positive on Wednesday, and her colleagues were later found to have the virus.
The identity of the initial patient is unclear, but around 70 to 80 people are reported to work at the call center.
Meanwhile, according to Cheongju City and LG Chem on Thursday, a 50-year-old working at one of the chemical company's factories in Chungcheongbuk-do Province tested positive the previous day, and was taken to Cheongju Medical Center.
With the help of the local health authorities, LG Chem has temporarily closed the factory and is contact tracing others who might've been close to the patient.
As the number of cases suddenly increased in Cheonan and Cheonju City, the social distancing level will be raised to 1.5 from 6 PM Thursday.
Kim Bo-kyoung, Arirang News.